Flexible conductor.



D. T. MAY. FLEXIBLE CONDUCTOR. APPLICATION FILED APR.27, 1912.

Patented Nov. 3, 1914.

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DA VID T. OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY, OFNEW YORK, N. Y., A CORPORATION OF ILLINOIS.

FLEXIBLE coNnUcroa.

Specification of Letters Patent.

Patented Nov. 3, 1914.

To all whom it may concern Be it known that I, DAVID. T. MAY, citizen ofthe United States, residing at New York, in the county of New York andState of New York, have invented a certain new and useful Improvement inFlexible Conductors, of which the following-is a full, clear, concise,and exact description. 7

This invention relates to flexible conductors, and particularly toflexible conductors for use in making telephone switchboard cords.

An object of this invention is the production of a cord which will haveall the advantages ofthe tinselcord of ordinary type as regardsflexibility, and all the advantagesof the steel cord as regards"durability without any of the disadvantages common to either. 7

This invention covers a conductor in which individual twists composing astrand are so laid together that the tape of each twist is tightened onthe thread in the process of making the strand, and the strands aretwisted together 'into a rope which has no central core, the wholeconstruction resulting in a conductor of high efliciency.

In the drawing, the figure shows a section of cord constructed inaccordance with ployed.

A thread 10, having a tape 11 of conduiztingmaterial wound thereon,forms a twist or a tinsel thread '9; 'A plurality of twists 9 are laidtogether, in a close spiral, with a right-hand lay; that is, in such away that the tape 11 of each twist 9 is tightened on the thread 10thereof. The laying together of the twists 9 results in a strand 12.Three strands 12 are then laid directly together with alefthand lay toform a conductor 8. In the completed conductor 8 the. relation betweenthe lengthof lay (that is, the linear advance in making a complete turn)in each strand and the length of lay in-the whole conductor is such thatthere is no tendency for the conductor to kink or untwist. The conductorresulting from the laying together of the strands 12 is'then wrappedwith two servingsv of insulation 13 and 14 wound tightly on theconductor in opposite directions, after which a braiding of cotton orsilk 15 is placed thereon, as is usual. Three of these conductors arethen taken and twisted together in thevform of a rope without any corebeing used; and after twisting, threads of ordinary cotton 16, 17 and18, are used for the purpose of making a smooth finish on the outside ofthe. cord.

In twisting the three insulated conductors together, no attempt is madeto form them to prevent separation of the conductors asthe resultingcore is wrapped with a spaced serving of cotton 19, which accomplishesthe same purpose. Over the resulting core is then braided a covering ofglazed cotton 2-0, or other suitable material.

What is claimed is:

1. In a flexible conductor, a plurality of twists each comprising athread and a conducting tape wound thereon, saidtwists forming a strandlaid together in a direction to tighten the tape on each individualthread, and a plurality of such strands laid together in a directionopposite to that of each strand, the relation between the length of layin each strand and the length of lay in the whole conductor being suchthat there is no tendency for the conductor to kink or untwist.

2. In a flexible conductor, a plurality of twists, each comprising athread and a conducting tape wound thereon, said twists forming a strandlaid together in a close spiral and in a direction to tighten the tapeof each twist. and a plurality of such strands laid directly together ina close spiral and in a direction opposite to that of said twists, the"relation between the length of lay in each strand and thelength of layin the Whole conductor being such that there is no tendency for theconductor to kinkor untwist.

v3. The method of making a flexible conductor, which consists in windinga conducting tape about a thread thereby forminga twist, layingtogetherla plurality of such twists in a direction to tighten the tapeof each twist thereby forming a strand, and laying together a pluralityof such strandsin a direction opposite -to that of ing a twist, layingtogether a plurality of the whole conductor that there is no tendsuchtwists in a direction to tighten the ency for the conductor to kink oruntwlst. 10

tape on each twist thereby forming a strand, In witness whereof, Ihereunto subscribe and laying a plurality of such strands dimy name this25th day of April A. D., 1912. rectly together in a close spiral and ina DAVID T. MAY. direction opposite to that of the twists and Witnesses:

with such a relation between the length of F. TOOHEY,

lay in each strand and the length of lay in WALTER F. HOF MAN;

